Design and technological solutions for restoring the stability of earthen dams of reservoirs (on the example of the Orilsk reservoir)

Abstract

Goal. To assess the technical condition of fixing the upper slope of the Orilsk earthen dam, develop design and technological solutions to restore its stability. Methods. The work to determine the technical condition of the dam structural elements was carried out in 2024 in accordance with the Methodology for field surveys of earthen dams and protective dams for water management purposes using system analysis, calculation, experimental and statistical methods, mathematical modeling method, as well as visual surveys, photo fixation, nondestructive, and topographic geodetic surveys. Results. The data of field surveys indicated destructive deformation processes caused by the action of wave and ice loads, primarily within the zone of water level fluctuations in the reservoir. It was confirmed that one of the main reasons for the destruction of the upper slope of the dam was the activation of the mechanical suffosion process — the removal of soil from the base of the filter layer of the formation drainage and, as a result, the subsidence of the mount from the stone cape and its sliding into the reservoir zone. The design parameters that will ensure the stability and reliability of fastening the upper slope, in particular the dimensions of the stone (calculated and the largest) and the thickness of the cape, were clarified. Conclusions. A fundamentally new technical solution is proposed for the creation of a fastened dam made of stone cape, which consists of a multi-layer structure made of various-sized stone laid on a geosynthetic screen, and the technology for arranging this structure during the restoration of the upper slope of the Orilsk earthen dam. Analytical calculations confirmed the design and technological parameters that ensure the stability and reliability of the protection of the upper slope of the bank.